WASHINGTON – President Bush said Thursday that, once his buildup of forces improves security in the Iraqi capital, he intends to follow the troop withdrawal plan proposed last winter by a bipartisan study group – a recommendation he all but ignored when it was originally made.

Speaking at a White House news conference, Bush for the first time fully adopted the blueprint outlined in December by the Iraq Study Group, saying he envisions U.S. troops gradually moving out of their current combat roles and into support and training functions.

“You know, I would like to see us in a different configuration at some point in time in Iraq,” Bush said, referring to the study group by the names of its co-chairmen, former Secretary of State James Baker III and ex-Rep. Lee Hamilton, D-Ind. “The recommendations of Baker-Hamilton appealed to me.”

Bush’s remarks were the clearest yet on his vision for the long-term U.S. role in Iraq.

It also represents a significant shift in his public position on the study group’s recommendations, which were embraced by war critics when they first were unveiled but largely ignored by the White House.

Despite Thursday’s public shift, Bush made clear that he did not necessarily see the move to a more limited role for U.S. troops coming soon, emphasizing that tamping down violence using his current “surge” strategy must take precedence.

“I didn’t think we could get there unless we increased the troop levels to secure the capital,” he said.

Still, he said the next phase of the war would have U.S. troops train Iraqis, guard the country’s borders and pursue Al-Qaida. Bush did not, however, explicitly endorse the study group’s specific targets for troop reductions.

Some congressional Republicans welcomed Bush’s new stance. Virginia Sen. John Warner, a key bellwether of the party’s position on the war, said he wanted Bush to move more quickly in implementing the study group’s recommendations, suggesting the White House shift strategy as soon as July.

“The facts on the ground, if they continue to worsen as they have been here in the past months, then it seems to me that (July) would be an opportune time” for a shift, Warner told reporters.

Defense Secretary Robert Gates has suggested that a reduction in troops could begin as soon as September, when the Pentagon has promised a formal evaluation of the effectiveness of the current buildup.

Thursday, however, Gates declined to say when a shift to the new posture would occur. “It remains to be seen,” he said at a news briefing. He said planning for a reduction was under way, as part of contingency planning he ordered several months ago.

When Bush unveiled his new Iraq buildup strategy in January, it was seen as a repudiation of the Iraq Study Group.

Since then, however, several key Republicans have begun to question the administration’s strategy, as public support for the war has continued to wane. A New York Times/CBS News poll issued Thursday showed that 61 percent of Americans now believe that the United States never should have invaded Iraq.

Bush’s sudden embrace of the study group’s blueprint is a measure of how far support for the war has eroded.

It also is a sign that supporters of the Iraq Study Group’s recommendations within the administration are gaining ground in the internal debate over the way forward.

The recently named White House “war czar,” Army Lt. Gen. Douglas Lute, is known to be a supporter of a more limited role for U.S. combat troops. He initially opposed the surge, when it was being debated within the Pentagon.

When the Iraq Study Group delivered its report to the White House last year, Bush said he agreed with its assessment of the dire situation inside Iraq, but he made clear that he did not share its conclusions, particularly those on troop withdrawals.

“Not all of us around the table agree with every idea,” Bush said at the time.

Gradually, however, the administration has moved closer to the study group’s recommendations.